Obesity is the most common nutritional disease of companion pets such as dogs and cats in an affluent society. It in fact exceeds by far all deficiency diseases combined. Obesity generally is considered present when body weight of the companion pet is 15% or more greater than optimum, which is the point at which health problems begin increasing with increasing weight. It has, for example, been reported that in affluent societies from 24% to 44% of the dogs are obese. Generally speaking, the incidence of obesity in companion pets increases with the age of the pet. Similar to humans, as the animals age body fat increases, and the amount of lean body mass decreases. For dogs particularly, obesity is more common in females than males up to age 12 years.
Because obesity develops gradually, the companion pet owner is often unaware of the overweight condition until it is called to his or her attention. Rarely is an animal presented to a veterinarian solely for the problem of obesity, but instead because of dermatitis, shortness of breath, routine immunizations, or arthritic or rheumatic symptoms. It is not uncommon that obesity is the predisposing cause of the condition noticed by the owner, although the obesity itself may not be noticed. For example, in one study it was observed that nearly one-third of the owners of obese dogs did not realize that their dogs were overweight.
The cause of obesity in companion pets is quite simple--energy intake in excess of that utilized. However, the factors causing this are not quite so simple. Some dogs are known to be "easy keepers". That is, they become overweight while being fed commercial dog foods in amounts adequate for normal adult maintenance, and in the same amount and manner as their kennel mates who may maintain optimum weight.
In most instances, in companion pet obesity there are two stages--an initial phase and a static phase. The basic cause of the initial phase is a dietary energy intake in excess of that utilized, resulting in a positive energy balance which is deposited as fat. In the static phase, dietary intake is reduced in accordance with energy needs so that body weight remains constant in the obese state. Thus, the amount of food required to maintain the animal in obese state is no greater, and in fact is often less, than that required to maintain the normal, non-obese state.
Thus, the only successful way for reducing companion animals is a drastic food intake reduction. When this occurs, the companion pets often scavenge and/or beg for food because of the sensation of constant hunger. As a result, the animal finds additional food, or pet owners feed the animal to stop the begging with the result being that no weight reduction occurs.
In short, it can be seen that for companion pets successful weight reduction involves not only decreased food intake, but as well an interdisciplinary, psychological treatment that involves the interrelationship between the companion animal and its human owner. This complex psychological interdependency makes weight reduction in companion pets even more difficult than it otherwise might be. In short, success at pet weight reduction involves initially convincing the owner that weight reduction is needed; secondly, the animal's food intake must be decreased for a sustained and regular period of time sufficient for weight reduction to occur; and third, the animal must be inhibited from constant scavenging and/or begging which tempts the owner to give in and increase the food intake to stop the begging.
In the past, certain drugs have been used in the treatment of obesity in mammals, including companion pets. These include drugs which decrease appetite such as amphetamines, drugs which cause nausea, decrease intestinal absorption, or increase metabolic rate such as thyroid hormones, and finally, drugs which either tranquilize or act as diuretics. None of the above have been generally effective. They often cause side effects, and tests of most have shown that such drugs are not only expensive, but ineffective in that when free choice fed with food, the animals often tend to avoid the food that contains the drug.
It therefore can be seen that there is a real and continuing need for a treatment for mammals, and especially companion pets, which is safe, efficacious, and which can successfully result in obesity reduction without changing the animal's behavioral patterns to such an extent that its relationship with its owner is changed. This invention has, as its primary objective, the fulfillment of this need.